Elastomericlly spring railway truck bolster

ABSTRACT

A three piece bogie for a railway vehicle in which the resilient connecting means between each solebar or side frame and the bolster comprises spring support means for vertical loads and at least two spaced-apart inter-engaging pairs of resilient members, one element of each pair mounted on the bolster and one on the solebar or side frame wherein the elements may only move relatively in a vertical direction and horizontal movement is resisted, of which the following is a specification.

United States Patent [191 Harrison Dec. 25, 1973 ELASTOMERICALLY SPRINGRAILWAY TRUCK BOLSTER [75] Inventor: Reginald Harrison, Oadby, England[73] Assignee: Dunlop Limited, London, England [22] Filed: Jan. 31, 1972[21] Appl. No.: 222,081

[30] Foreign Application Priority Data Feb. 3, 1971 Great Britain3,765/71 [52] U.S. Cl 105/197 A, 105/224.l, 267/3 [51] Int. Cl. B61f3/08, B6lf 5/08, B61f 5/12 [58] Field of Search 105/197 R, 197 A,

2,617,366 11/1952 Piron 105/197 A 3,512,482 5/1970 Lich lO5/224 l2,410,402 ll/l946 Ledwinka IDS/224.1

Primary Examiner-Gerald M. Forlenza Assistant ExaminerH0ward BeltranAlt0rneyRichard K. Stevens et a1.

[5 7 ABSTRACT [56] References Cited movement is resisted, of which thefollowing is a spec- UNITED STATES PATENTS lficatlon- 2,754,768 7/1956Hile 105/197 R 5 Claims, 3 Drawing Figures 5 P L J m :fz;

m H L J PATENTED DEC 2 5 I975 SHEET 3 BF 3 ELASTOMERICALLY SPRINGRAILWAY TRUCK BOLSTER This invention relates to suspension systems forrailway vehicles and in particular for railway vehicle bogies of thethree-piece type.

A three-piece bogie comprises a bolster, for pivotal connection to theunderframe of the vehicle, extending across the central region of thebogie and two solebars or side frames. Each solebar or side frame isconnected at its center to one end of the bolster and carries anaxle-box at each of its ends. The arrangement of the bolster andsolebars or side frames is generally that of an H. A wheel and axle setis mounted at each open end of the bogie and supported in two axleboxes,one at the end of each solebar or side frame.

The connections between the bolster and solebars are not rigid andspring means are provided at this connection. A common form of springingis a pair of rubber chevron springs and this provides the only springingfor low speed use. For high speed use primary suspension may be providedbetween each axlebox and the solebar and then the solebar to bolstersuspension is the secondary suspension for the bogie. The primarysuspension is of short travel and most suspension deflection is allowedin the secondary suspension.

In both arrangements to accommodate track irregularities one wheel mustbe allowed to rise and fall with respect to the other three and theflexibility at the bolster to solebar suspension must be arranged toallow this or in the case of the high speed bogie some of this movement.(The primary, or axlebox suspension cannot provide sufficient deflectionand at the same time provide satisfactory suspension properties for thelarge differences between laden and unladen conditions of a freightvehicle).

' Hitherto three-piece bogies in which the suspension allows sucharticulation of the solebars in the vertical plane have been prone tolozenging and loss of alignment between the solebars due to a lack ofrigidity in the horizontal plane caused by the spring means between thebolster and solebars or side frames. When the bogie enters or leaves acurved section of track the turning movement applied by the track andflange causes the parallelogram formed by the axles and solebars todeflect or lozenge and the resultant mistracking of the two wheel andaxle sets causes excessive track and tread wear.

It is an object of the present invention to provide a three-piece bogiein which is provided solebar articulation in the vertical plane andresistance to lozenging.

According to one aspect of the present invention a railway vehicle bogiecomprises a bolster, two solebars or side frames and resilientconnecting means between each solebar and the bolster wherein eachconnecting means comprises spring support means for vertical loads andat least two spaced-apart interengaging pairs of resilient elements, oneelement of each pair mounted on the bolster and the other elementmounted on the solebar wherein one element may move with respect to theother element only in a substantially vertical direction, horizontalmovement being resisted.

In a preferred arrangement the resilient connecting means between thesolebar and bolster comprises a compression spring comprising blocks ofelastomeric material bonded between metal plates and two spacedapartelastomeric material bushes, the bushes having an internal and externalsteel tube bonded thereto. The internal steel tubes are attached to thesolebar and the external steel tubes are attached to the bolster thustaking some of the tare load in shear. The resultant assembly providesthe required characteristics in the manner described below.

Other features of the invention will be apparent from the followingdescription of one embodiment of the invention in conjunction with theaccompanying informal diagrammatic drawings in which:

FIG. 1 is a plan view of a bogie assembly;

FIG. 2 is a part-sectional side view of the bolster-tosolebar connectingmeans and,

FIG. 3 is a part-sectional plan view of the detail shown in FIG. 1.

In FIG. I the two wheels, 1, 2 on one side of a bogie are supported inaxleboxes mounted at either end of a solebar or side frame 3. Thesolebar or side frame 3 is of generally rectangular section and thedepth of the section is greater at the central portion as shown inFIG. 1. A rectangular aperture 4 is provided through the solebar or sideframe 3 in a horizontal direction with regard to the bogie assembly.

The solebar or side frame arrangement at the other side of the bogie isthe same as described above and the two apertures 4, one in each solebaror side frame, are used for connection to a bolster 5 extending acrossthe bogie assembly.

The connection from bolster 5 to solebar or side frame 3 is obtained bymeans of a substantially flat central end portion 6 on each end of thebolster which is arranged to project through a rectangular solebar orside frame aperture 4. Between the lower surface of the end portion 6and the lower surface of the rectangular aperture 4 is placed a rubbercompression spring 7. The spring 7 comprises two disc-shaped metal endplates 8 and 9 and a pair of disc-shaped rubber blocks 10 interleaved bya similarly-shaped metal plate 1 1. Each metal to rubber interface isbonded to provide the integral spring 7. Either side of the flat centralend portion 6 of the bolster is an extension 12 and through eachextension a hole 13 is bored in the vertical direction with respect tothe bogie assembly.

Two bonded metal-to-rubber bushes 14, 14A are force-fitted one into eachhole. Each bush has an inner and outer steel tube 15, 16 mountedconcentrically and the space between the steel tubes is filled by rubber17. The inner steel tube 15 is force-fitted onto a steel cylinder 18which is bolted to an upstanding boss 19 on the lower surface of therectangular aperture 4.

The connection between the bolster 5 and the solebar or side frame 3acts as follows:

In a vertical plane with respect to the bogie each solebar 3 isresiliently supported from the bolster S by means of the rubber spring 7which is under compression. Again in the vertical plane the wheel I maymove upwardly with respect to the wheel 2 by pivotting the solebar 3about the center of the spring 7. This movement causes both rubberbushes 14, 14A to be deflected axially by movement of the inner tubewithin the outer tube and as the bushes have little resistance to thismovement the movement is allowed. In some cases the resistance of thebushes to axial deflection may be used also to contribute to the supportof the vertical load. Alternatively, if a large deflection is to beallowed the bushes may be pre-deformed in the unladen condition so thatin the change to laden condition the bushes are moved through theirnatural unstressed condition.

In the horizontal plane with respect to the bogie assembly the bolster Sis normally at right angles to the solebar 3. Track to wheel forces actto deform the bogie structure by changing this relationship by pivottingthe solebars with respect to the bolster about the center A (see FIG. 3)which is the center of the rubber spring 7. This is the lozengingmovement earlier referred to and is resisted by the spaced-apart rubberbushes l4 and 14A which have a high resistance to deflection in anydirection in the plane perpendicular to their longitudinal center-lines.

While the embodiment described utilizes rubber for the springs 7 andbushes l4, l4A any elastomeric material having the requisite strengthand fatigue properties may be used.

Furthermore, the springs 7 may be replaced by nonelastomeric springmeans, for example coil springs.

The bushes 14, 14A may also be replaced by sliding metal-to-metal guidesbut in this case some resilient mounting at either the attachment to thebolster or to the solebar or side frame 3 is needed so that the requiredmovements are allowed.

More than two rubber bushes may be employed at each bolster to solebaror side frame connection and the bushes may be used, by the use of asuitable elastomer, to contribute to the support of the load from themain springs 7 and/or to contribute to damping of solebar or side framearticulation in the vertical plane.

The advantages allowed by the suspension described may be summarised asfollows:

1. The radially loaded bushes resist lozenging. 2. Sideframearticulation is provided to allow all the wheels to remain in contactwith the track despite track irregularities. 3. Load equalizationbetween the wheels of a vehicle is allowed by the articulation for allload conditions. 4. The bogie construction retains the simplicity,lightness and cheapness of the simplest threepiece bogie.

I claim:

1. A railway vehicle bogie comprising a bolster, two

solebars and resilient connecting means between each solebar and thebolster wherein each connecting means comprises elastomeric springsupport means for vertical loads and at least two spaced-apartinterengaging pairs of resilient elements, each interengaging pair ofelements comprising parallel internal and external steel tube,concentrically arranged and interconnected by means of a bush ofelastomeric material bonded between the steel tubes, one element of eachpair being mounted on the bolster and the other element being mounted onthe solebar so that one element may move with respect to the otherelement only in a substantially vertical direction, horizontal movementbeing resisted.

2. A railway bogie according to claim I wherein the spring support meanscomprises a compression spring comprising a block of elastomericmaterial bonded between metal plates.

3. A railway bogie according to claim 2 wherein at least two blocks ofelastomeric material comprise each spring and a metal interleaving plateis provided between adjacent blocks and bonded thereto.

4. A railway bogie according to claim 1 wherein the external steel tubeof each pair of elements is mounted on the bolster and the inner steeltube of each pair of elements is mounted on the solebar.

5. A railway vehicle bogie comprising a bolster, two solebars andresilent connecting means between each solebar and the bolster, eachconnecting means comprising:

a. spring support means for vertical loads having at least oneelastomeric element having its center substantially alined with thecenter of the bolster;

b. means to permit substantially vertical movement and resist horizontalmovement of a solebar in relation to the bolster comprising at least twospacedapart interengaging pairs of resilent elements each element havingparallel internal and external concentric cylindrical steel tubeextending parallel to each other and interconnected by a bush ofelastromeric material bonded between the steel tubes.

l l l= =l=

1. A railway vehicle bogie comprising a bolster, two solebars andresilient connecting means between each solebar and the bolster whereineach connecting means comprises elastomeric spring support means forvertical loads and at least two spacedapart interengaging pairs ofresilient elements, each interengaging pair of elements comprisingparallel internal and external steel tube, concentrically arranged andinterconnected by means of a bush of elastomeric material bonded betweenthe steel tubes, one element of each pair being mounted on the bolsterand the other element being mounted on the solebar so that one elementmay move with respect to the other element only in a substantiallyvertical direction, horizontal movement being resisted.
 2. A railwaybogie according to claim 1 wherein the spring support means comprises acompression spring comprising a block of elastomeric material bondedbetween metal plates.
 3. A railway bogie according to claim 2 wherein atleast two blocks of elastomeric material comprise each spring and ametal interleaving plate is provided between adjacent blocks and bondedthereto.
 4. A railway bogie according to claim 1 wherein the externalsteel tube of each pair of elements is mounted on the bolster and theinner steel tube of each pair of elements is mounted on the solebar. 5.A railway vehicle bogie comprising a bolster, two solebars and resilentconnecting means between each solebar and the bolster, each connectingmeans comprising: a. spring support means for vertical loads having atleast one elastomeric element having its center substantially alinedwith the center of the bolster; b. means to permit substantiallyvertical movement and resist horizontal movement of a solebar inrelation to the bolster comprising at least two spaced-apartinterengaging pairs of resilent elements each element having parallelinternal and external concentric cylindrical steel tube extendingparallel to each other and interconnected by a bush of elastromericmaterial bonded between the steel tubes.